Apparatus for making composite glass



May 26, 1931. w, OWEN APPARATUS FOR MAKING COMPOSITE GLASS Filed June 1, 1928 2 Sheets-Sheet l May 26, 1931. w, OWEN APPARATUS FOR MAKING COMPOSITE GLASS Filed June 1, 1928 2 Sheets-Sheet 2- came as, 1931 UNITED STATES PA EN OFFICE wnmnu Om, OI PITTSBURGH, PENNSYLVANIA, ASSIGHOB TO PITTSBURGH PLATE GLASS 001mm, A CORPORATION Olj' PENNSYLVANIA mm'msron name concerncuss Application fled June 1,1928. Serial Io. 20am.

The invention relates to apparatus for making composite glass, -where1n,heat and pressure are applie to cause a joinder between the glass and celluloid or other pyroxylin plastic sheet. Composite glass ordinarily comprises two sheets of glass with a sheet of celluloid or equivalent material cemented therebetween, although a greater number of sheets may be employed. It is the ractice to assemble the sheets with a coating of cement, such as gelatin, dried upon the surfaces of the glass sheets which are to becemented to the celluloid, the heat subsequently applied serving to soften the gelatin l5 and secure adhesion when pressure is applled. The present invention has for its primary objects, the provisions of an improved construction which can be operated with rapidity and with a small percentageof breakage. Certain embodiments of the mventlon are illustrated in the accompanying drawin wherein:

igure 1 is a vertical section through one form of the construction. Fig. 2 is a perspective view of one of the rubber containers used in the Fig. 1 construction. Fig. 3 is a vertical section through another form of construction. And Fig. 4 is a perspective view of the rubber container used in the con-v struction of Fig. 3.

Referring to Figs. 1 and 2, the numerals 1 and 2 designate a pair of opposing metal platens which have their faces recessed so as to carry the rubber containers 3 and 4. The platens are provided with a plurality of passages 5, 5 through which steam and water may be circulated for successively heating and cooling the platens, suitable connect1ons being made with the necessary steam and water supply pipes. The platens are separable, and for convenience in handling and moving them toward and from each other, they may be mounted in a press such as that shown in 45 the application of W. O. Lytle, Serial Number 164,511. In operation, the platens are separated so that the sheets to be joined together may be conveniently positioned between the rubber containers, after which the 59 platens are moved together and securely clamped in this position during the pressing and heating operations.

As shown in Fig. 1, the pair of glass sheets 6 and 7 are shown in position u on the container 4, with the sheet of cell oid 8 interpipes 9 and 10 connected to a suitable source of pressure, and after the platens have been brought together, pressure is supplied through the pipes to any desired extent, a pressure of about 150 pounds per square inch having been found satisfactory. The containers are also provided with exhaust pipes 9a (Fig. 2) by means of which the water in the containers may be withdrawn, if desired. The spacing strips 11 are" employed along the edges of the sheets in order to prevent too great pressure on the edges of the sheets which tends to thin the pyrolin and squeeze it out. After the ap lication of pressure, steam is circulated t ugh the passages 5, 5, heating the latens, the containers 3 and 4 withthe liqui therein and the set of plates between the containers. The temperature of the sheets is brought to about 250 degrees F., which gives the necessary softening of the cement and celluloid in order to make a proper union between the sheets. After the temperature and pressure above indicated have been arrived at, the flow of steam through the passages 5 is substituted byone of water. and this is continued until the glatens and the parts therebetween have een reduced in temperature so that the composite plate formed between the containers can be convenientlyhandled. During this drop in temperature, the pressure is maintained in the containers, as this has-been found necessary in order to secure a satisfactory joinder of the sheets. After the .parts have been sufliciently reduced in temperature, the pressure is released and the platents 1 and 2' are separated and the set of sheets, now securely joined to ether; to form a composite plate, are remove from the press.

' ens each provide In the construction of Figs. 3 and 4, the members 12 and 13 are relatively fixed, the structure being preferably in .the form of a cabinet as shown in my Patent No. 1,657,227. Fitting snu ly between the members 12 and 13 is a metal container comprising the plates 14 and 15 hinged together at 16 and adapted to carry the rubber containers 17 and 18. These containers are adapted to ca between them the three sheets 19, 20 and 21 to be joined together, such sheets being preared as described in connection with ig. 1.

uitable spacing strips 22 are provided around the edges of the sheets the same as in the Fig. 1 construction. Each container is provided with a pair of pi e connections 23 and 24 by means of who water under pressure may be circulated through the containers.

In using this form of apparatus, hot water is first circulated through t e containers until the sheets 19, 20 and 21 arrive at a temperature of about 250 degrees F. and the pressure, in the containers is brought to about 150 pounds er square inch. After this temperature an pressure have been attained, the temperature of the circulating water is reduced, the pressure being maintained, however. This operation is continued until the temperature of the circulated water is at a minimum and the sheets are cooled down to a temperature at which they may be,conveniently handled, after which the pressure is released and the lates14 and 15 are removed from between tl fe members 12 and 13 and opened so that the composite plate formed therebetween may be removed.

WlKit I claim list 1 h d 1. pparatus or app ying eat an pressure to a plurality of sheets to be joined together comprising, a pair of opposing platens each provided with an outwardl opening recess having a substantially fl at rear wall and edge walls extending transversely of the rear wall to the faces of the platens,

rubber containers seated in the recesses and supported at their edges by the edge walls of the recesses and ada ted to receive between them the sheets to he joined, said edge walls bein rounded outwardly, means for supplyingh quid under pressure to the interior of e containers, and means for aifecting predetermined temperature changes in sald liquids.

2. Apparatus for applying heat and pressure to a plurality of sheets to be joined together comprising, a pair of opposing platwith an outwardl openmg recess having a substantially at rear wall and edge walls extending transversely of the rear wall to the faces of the platens, and having back of said recesses passages foe receiving and cooling fluids, rubber containers seated in the recesses and sup rted at their edges by the edge walls 'of e re-.

cesses and adapted-to receive between them the sheets to be joined, means for suppl 'ng liquid under pressure to the interior 0 the containers,-and means for successively circulating a heatingdluid and a cooling fluid through said passages; said-edge walls being rounded outwardly. v

3. Apparatus for applying heat and pressure to a. plurality of sheets to be 'oined comprising a pair of opposing separa le platens, one of which is rovided with an outwardly opening recess avin a substantially flat rear wall and outwanfiy curving ed e walls extending transversely of the rear wa to the face of the platen, a flat rubber container seated in said recess and supported at its edges by said edge walls so that the sheets to be joined together may be positioned between the outer face of the container and the face of the 0p osing platen, means for suppl 'ng fluid un er pressure to the interior 0 the container, and means whereby one of the platens is heated.

In testimony whereof, I have hereunto subscribed my name this 17th day of May, 1928.

OWEN.

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